Journal of Hazardous Materials 177 (2010) 28–41 Contents lists available at ScienceDirect Journal of Hazardous Materials journal homepage: www.elsevier.com/locate/jhazmat Review Application of vegetable oils in the treatment of polycyclic aromatic hydrocarbons-contaminated soils C.L. Yap a , S. Gan a,∗ , H.K. Ng b a Department of Chemical and Environmental Engineering, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia b Department of Mechanical, Materials and Manufacturing Engineering, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia article info Article history: Received 7 August 2009 Received in revised form 21 October 2009 Accepted 12 November 2009 Available online 18 November 2009 Keywords: Polycyclic aromatic hydrocarbons (PAHs) Vegetable oil Soil remediation Contaminated soil abstract A brief review is conducted on the application of vegetable oils in the treatment of PAH-contaminated soils. Three main scopes of treatment strategies are discussed in this work including soil washing by oil, integrated oil-biological treatment and integrated oil-non-biological treatment. For each of these, the arguments supporting vegetable oil application, the applied treatment techniques and their efficiencies, associated factors, as well as the feasibility of the techniques are detailed. Additionally, oil regenera- tion, the environmental impacts of oil residues in soil and comparison with other commonly employed techniques are also discussed. © 2009 Elsevier B.V. All rights reserved. Contents 1. Introduction .......................................................................................................................................... 29 2. Physical extraction ................................................................................................................................... 29 2.1. The role of vegetable oil in desorption, solubility and extraction of PAHs .................................................................. 29 2.2. Oil/soil extraction system .................................................................................................................... 32 2.3. Oil/water/soil extraction system ............................................................................................................. 32 2.4. Associated factors ............................................................................................................................ 32 2.5. Feasibility ..................................................................................................................................... 32 3. Integrated oil-biological treatment .................................................................................................................. 32 3.1. The role of vegetable oil in enhancing biodegradation ...................................................................................... 33 3.1.1. Enhanced mass transfer through physiochemical process ........................................................................ 33 3.1.2. Increased surface area for microbial contact ....................................................................................... 33 3.1.3. Reduced surface tension by oil components ....................................................................................... 33 3.1.4. Enhanced biosurfactant production ................................................................................................ 33 3.1.5. Extra carbon and energy source .................................................................................................... 34 3.1.6. Initiation of degradation by MnP-mediated lipid peroxidation ................................................................... 34 3.1.7. Enhanced PAH degrading enzyme production ..................................................................................... 35 3.1.8. Selective enrichment of PAH degrading microbes ................................................................................. 35 3.2. Sequential bioslurry treatment with post-two-liquid phase (TLP) extraction .............................................................. 36 3.3. Bioslurry treatment .......................................................................................................................... 36 3.4. Solid phase composting ...................................................................................................................... 36 3.5. Sequential in situ biotic and abiotic treatment .............................................................................................. 36 3.6. Associated factors ............................................................................................................................ 36 3.7. Feasibility ..................................................................................................................................... 36 4. Integrated oil-non-biological treatment ............................................................................................................. 37 5. Vegetable oil regeneration ........................................................................................................................... 37 ∗ Corresponding author. Tel.: +60 3 8924 8162; fax: +60 3 8924 8017. E-mail address: suyin.gan@nottingham.edu.my (S. Gan). 0304-3894/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.jhazmat.2009.11.078